Fred Astaire launched his non-musical, dramatic acting career with this film. Stanley Kramer couldn't decide who to cast in this role until his wife suggested Astaire while watching one of his films on TV.
The movie was filmed in 1959. For one year (July 4, 1959 - July 4, 1960) the US flag had 49 stars. In the opening scene a 49-star flag can be seen flying from the submarine.
The film had its world premiere on December 17, 1959 in more than 20 cities worldwide, including Moscow. It was the first time an American film had had a premiere in the Soviet Union. The special premiere in Moscow was held at a workers' club, with the attendance of 1200 Soviet dignitaries, the foreign press corps, diplomats, and US Ambassador Llewellyn Thompson. Gregory Peck and his wife traveled to the Soviet Union for the premiere.
This was Hollywood's first large-scale film to address the possibility of nuclear Armageddon.
It is rumored that guards at each end of the Golden Gate Bridge were paid $500 each to stop cars for a minute to get footage of an empty bridge.